An image forming apparatus is known which has a tray print function to perform printing on sheets (recording mediums) stacked in a sheet feed tray (stacking unit), and a manual print function to perform printing on sheets inserted from a manual feed slot by a user. For example, in the above described image forming apparatus, a transport path of a sheet from the manual feed slot and a transport of a sheet from the sheet feed tray are joined together before a registration roller, and continue on downstream to the image forming unit on the downstream side. In such an image forming apparatus, for example, when a print operation starts, it is detected whether or not a sheet is inserted from the manual feed slot, and when a sheet is detected, the sheet is fed to the image forming unit, and print is performed. Meanwhile, when a sheet from the manual feed slot is not detected, a sheet from the sheet feed tray is fed to the image forming unit, and print is performed.